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- P. Nenzi, G. Bazzano, F. Marracino, L. Picardi, C. Ronsivalle, V. Surrenti, M. Vadrucci
ENEA C.R. Frascati, Frascati (Roma), Italy
- F. Ambrosini
University of Rome La Sapienza, Rome, Italy
- F. Ambrosini
Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy
- M. Balucani, A. Klyshko
University of Rome "La Sapienza", Rome, Italy
- C. Snels, M. Tucci
ENEA Casaccia, Roma, Italy
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The irradiation of silicon with ion beams is an established technique to modify its properties. Protons are used for micromachining applications, in conjunction with porous silicon. Porous silicon does not form in areas irradiated with a given fluence of protons (>1014 cm-2). Our work concentrated on the applicability of masked irradiation of silicon wafers with 1.8 MeV proton beams delivered by the TOP-IMPLART LINAC. In our experiments 1-10 Ω*cm n,p-type silicon wafers were masked and irradiated with protons at fluences between 1014 and 1015 protons/cm2. Porous silicon did not form in the irradiated areas up to a distance from the surface corresponding to the stopping range (30um). The suppression of porous silicon formation is due to the to the neutralization of dopant impurities by implanted protons that increases the local resistivity. The interest in using RF LINAC for micromachining applications lies in the possibility of deep implantation, that allows the realization of 3D structures for MEMS applications. The use of metal masks with uniform beams, instead of scanned micro- and nano-metric ion probes, increases throughput achievable in industrial processing of wafers.
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